Optimization of Symmetric gravity-arch Dams. Design rules

Abstract

Arch gravity dams are massive structures of important environment impact and economic investments with a complex structural behavior. This behavior is usually simulated by means 3-D Finite Elements with several layers across the dam thickness. Due to limited experienced existing for this type of dams a set of preliminary formulae have been obtained in order to compute the key parameters of the design definition, such as the slopes of upstream and the downstream faces of the dam, radius of the upper arch, with of the dam at the top level, etc. The methodology used to find the formulae consist in assuming a quadrilateral cross section for the valley where the dam will be located. The values to define the valley geometry are given as data. From these data and the concrete material properties, an arch gravity dam supporting a set of loadings combinations can automatically be designed with a minimum weight. In the analysis of this design the obtained stresses should be layed between some specified admissible limits. First and second order optimization procedures have been applied to a large set of valley configurations and the corresponding arch gravity designs have been found. Using this correspondence a regression analysis has been performed and the corresponding graph, design curves and regression polynomial functions between the valley data and the different dam design parameters have been obtained. Some conclusions about the importance of the data on the design parameters of an arch gravity dam are also presented.